Crane structure



Jan. 3, 1933. c. BURRILL ET AL CRANE STRUCTURE Filed May 21, 1952 2SheetsSheet l M w m m \l W? fi- EQWMQ m A mH- i @4 m M ir 1 G n n w m &3 mm 3 m w a rc 5 9 2 ATTORN E75 Jan. 3, 1933. c. BURRILL ET AL1,393,157

CRANE STRUCTURE Filed May 21, 1932 2 Sheets-Sheet 2 Patented Jan. 3,1933 UNHTED STATES FATENT 0FFE OF WALLSEND-UPON-TYNE ENGLAND, 1943M 1.

" 33 TO THE OETIEEUM DAVIT COM- PA'NY LIMITED, OF VIALLSEI-D-UPON-TZIIE, ENGLAND, A BRITISH. COMPANY CRANE ST BUOTURE Applicationfiled May 21, 1932, Serial No. 612,768, and in Great Britain May 30,1931.

This invention relates to improvements in crane structures, and isespecially directed to crane structures which comprise a rigid strutpivotally anchored at its lower end and having a rocking jibeccentrically pivoted at its upper end, the load be'ng suspended fromthe end of the longer arm of said jib.

The object or this invention is to provide an improved crane structurefor general purposes, and a further object of the invention is toprovide a light and inexpensive con-- struction for use n duplicate as aboat crane or davit for launching and picking up a ships boat, forlaunching and picking up hydroplane, or for analogous operations.

Another object of the invention is to provide a crane structure havingpower, uue to the balancing property of its weight, to lift the endotthe longer arm of the jib a predetermined amount automatically whenthe load is removed.

Another object of the invention s to provide improved means for swingingthe crane structure in a vertical plane about the heel pivot of itsstrut.

A further object of the invention is to provide improved means forpositively lmiting the inward swing of the crane structure.

With these and other objects in view, as will appear from the followingdescription, our invention consists in the novel features ofconstruction, combinations of elements and arrangements or partshereinafter fully described and set out in the appended claims.

In the accompanying drawings forming part of this specification and inwhich similar characters of reference denote like and correspondingparts throughout the several views Figure 1 is a side elevation of acrane structure embodying our invention intended for use as a boatdavit, the davit being shown in the inboard position Figure 2 is a frontelevation of the davit of Fig. 1

Figure 3 is a sectional elevation to a larger scale of a portion of theactuating means of the davit of Figs. 1 and 2;

Figure 1 is a similar view to Fig. 1 showing the davit in an outboardposition;

Figures 5 and 6 are similar views to Figs. 1 and 4 respectivelyillustrating an alternative construction; and

Figures 7 and 8 are similar views to Figs. 1 and 4 respectivelyillustrating another alternative construct-ion.

Referring more particularly to the specific form of the inventiondisclosed in Figs. 1 to l of the accompanying drawings, 10 is a strutcomprising an H-section girder to the ends of which are riveted a heel.fitting 11 and a top fitting 12. The heel fitting 11 is formed with akeel support 13 and lugs 1st through which are passed aligned horizontalpivots 15 journalled in a double bearing 56 firmly attached to the shipsdeck 16, said pivots being disposed parallel with the side 17 or" thevessel. The top fitting 12 is formed with a lug 18 through which ispassed a hori- Zontal pivot 19 on which are mounted spaced parallelplates 20 which form the rocking jib, the jib pivot 19 being parallel tothe heel pivots 15. The outboard arm 21 of the jib is longer than itsinboard arm The end o1 the boat 23 adjacent to the davitis suspended bya hook 21 from a pulley block 25, and the rope 26 for lowering andraising the boat is attached at 27 to said pulley block, and, afterpassing therearound, is passed around a pulley block 28 on a pin 29between the outboard ends of the jib plates 20, around a. pulley 30 onthe jib pivot 19, and around a pulley 31 carried by a cast bracket 32firmly secured to the deck 1 behind the heel pivts 15, and is then ledbetween iairleads 33 to a convenient bollard or a hand or power winchwhich, being the usual practice, we have not illustrated.

'1. he actuating member comprises a threaded shaft 34 adapted to hetravelled into and out of a sheath 85 the upper end of which is attachedto a pivot 36 at the inboard end of the jib 20. As shown best in Fig. 3,the lower end of the sheath is fitted internally with a nut 37 whichengages the threaded shaft 34; and is held stationary therein by dowels38. The lower end of the shaft 34: is keyed to a worm wheel 39 mountedwithin a carrier 40 formed with lugs 11 engaging a pivot 42 j ournalledin the upper end of the bracket 32 which forms a stationary anchoragetor the actuating member. The worm wheel 39 is revolved by a worm 43 theshaft 44 of which is journalled in the carrier 40 and is fitted with acrank handle 45. Byrevolving the handle 45 the Worm 43 is caused torevolve the worm wheel 39 and hence the shaft 8% which travels throughthe nut 37 in the sheath and, according to the direction of rotation,length ens or shortens the actuating member, the effect being to swingthe strut 1O outboard or inboard about its heel pivots 15. The sheath 35is char ed with lubricant, the lower end of the nut 37 being cupped at46 to fit snugly against t is carrier 10 against which it abuts when thedavit is in its inboard position.

The means for controlling the rocking motion of the jib 20 as the strut10 is swung outboard and inboard comprise a pair of tension rods 47 theupper ends of which engage the pivot 36 at the inboard end of the jib.The lower ends-oi the tension rods are formed with elongated eyes 48which engage pivots 4:9 projecting from the sides of the bracket 32about midway between the heel pivots 15 and the pivot 42 of the carrier40 of the actuating member. The elongated eyes 4:?) allow or a limitedlengthwise move ment of the rods? about their anchorages 1i i i In theinboard position, the strut 10 has an angle of about 60 to the deck 16.50 is a i wood chock attached to the face or the strut against which theside of the boat 23 bears when the strut is 1nboard. The keel 51 of theboat is received in the keel supports 13 on the heel fittin s 11 asshown in Pi 1.

Rope gripes 52 are slung around the boat to retain it in its inboardposition, one end of each gripe being attached at to the keel support 13and the other end being detachably connected by slip release gear o-lvtothe bracket 32.

It will be understood that the davit is duplicated, one davit beingprovided near each end of the boat. The davit-s stow directly behind thehooks 24- by which the boat is sus pended, and the two davits arecontained within the length of the boat. On the gripes 52 being removedand the handles do of the two davits being simultaneously operated toextend the actuating member 34, 35, the struts 10 with their rockingjibs 20 are swung outboard as shown in Fig. l. The length and anchoragesof the tension rods 47 are chosen so that the initial outboard movementof the pulleys 28 carrying the boat falls 6 is slightly upward asindicated by the dotand-dash line 55 in Fig. 1, and the keel 51 of theboat is raised clear of its supports 13 by the tension rods 47 whichalso take the load off the actuating member 36 35. The outboard travelof the struts is continued until there is a suitable'clearance betweenthe boat 23 and the ships side 17, and the boat is then trolled by asingle handle l5 which isdisposed at a'convenient height, and nomanipulation 01"" the boat falls 26 is necessary until theboat is at therequired distance from the side of the ship. The shipsboats can bedisposed end to end near the side of the deck, and the necessary stowagearea. minimized. The height of the davit'is small, and it can bearranged to operate between decks. The bcatcarrying capacity of the shipcan thus be increased, or free open deck spaces can be obtained on thetop deck. Where some or all of the boats are stowed in a tween deck,they are protected from the weather, and the wind resistance of a vesselis by this or; pedient considerably reduced. Alternative ly, with davitsof normal height, greater side clearance than is at p esent availablecan be obtained. the upper blocks 28 are arranged wit iin the platesQOof the jib, danger of a toppling block is avoided, and any tendency ofthe upper block to twist in relation to the lower block is reduced. Asthe range of stress in the actuating member S l, varies from compressionin the inboard position shown in Fig. l to tension in the outboardposition shown in Fig. 4:, the weight of the davit structure can bematerially reduced. The davit works equally well whether on the higherside or on the lower side, the ship has a list. i V

A nov'elfeature of our improved davit is its power, due to the balancingproperty of the weight of its structure, to lift the outboard end 29 ofthe ,jib a predetermined amount automatically when the load is removed.

Our invention is peculiarly applicable to cranes suitable for launchingand picki up from the sea hydroplanes and for other general purposes.For thesepurposes, the crane may be arranged to operate as a single unitor in pairs as desired, and may be mounted on a platform rotatableabouta pivot so that the structure can be rotated, or alter natively theplatform may be mounted on straight or curved runways.

When the structure is used a crane and the actuating member is arrangedto work in.

tension only, a wire rope may be iitted in place of the sheath 35 andthreaded shaft 3%- above described, said rope being lengthened andshortened as required by means of a winch or equivalent device operatedby power or by han v r Inthe modified construction illustrated in Figs.5 and 6, the tension rod 47 is dispensed with and in its place awedge-shaped chock 57 is attached to the underside of the jib 20. Thechock is so arranged that it abuts against the upper part of the strut10 as shown in F 5 when tie jib is in its inboard position and limitsthe inboard travel of the structure without affecting its freedom tomove outboard. Instead of the chock 57, short length of wire 58 may beattached between the strut 10 and the inboard end 22 of the ib as shownin Figs. 7 and 8. These arrangements are especially suitable for cranes.

In another alternative method of applying our invention and asillustrated in Figs. 5 and 6, the actuating member comprises a rack 59travelled by a pinion 60 in place of the sheath 35 and threaded shaft 3dabove described, the rack being retained in engagement with the pinionby a carrier 410 pivoted on the spindle of the pinion which is mountedin bearings in the bracket 32. The pinion is rotated by a handle 61 onits spindle.

In a further alternative method at apply ing our invention and asillustrated in F '7 and 8, the actuating member is attached to the innerarm 22 of the rocking jib as described above and comprises a tension rod62 pivoted at 63 to a crank 64: operated by hand through pinion gear 65mounted on the bracket 32 and rotated by a handle 66 or by ower.

l/Vhile we have described what we new con sider to be the preferredembodiment of our invention and several modifications, we wish it to beunderstood that these disclosures are by way of example, and thatvarious changes or modifications of a more or less minor character maybe made in the actual crane structure from those herein disclosed anddescribed without departing from the spirit of our invention. Wetherefore claim all such structures as may be said to fall fairly withinth scope of the following claims.

lVhat we claim as our invention and de sire to secure by LettersPatentis 1. In a crane structure comprisin a support, astrut pivoted atits foot to said support, a rocking jib eccentrically pivoted at thehead of said strut and means for suspending the load from the longer armof said ib, the combination of an actuating member pivotally attachedbetween the end of the shorter arm of said jib and an anchorage on saidsupport, means for lengthening and shortening said actuating member, andmeans for con trolling said jib.

2. In a crane structure comprising a support, a strut pivoted at itsfoot to said support, a rocking jib eccentrically pivoted at the head ofsaid strut and means for suspending the load from the longer arm of saidjib, the combination of an actuating member pivotally attached betweenthe end of the shorter arm of said jib and an anchorage on said support,means for lengthening and shortening said actuating member, and meansfor controlling said jib, said control means comprising a stop operatingbetween the jib and the strut.

S. l'n a crane structure comprising a support, a strut pivoted at itsfoot to said sup port, a rocking jib eccentrically pivoted at the headof said strut and means for suspending the load from the longer arm ofsaid jib, the combination of an actuating member pivotally attachedbetween the end of the shorter arm of said jib and an anchorage on saidsupport, means for lengthening and shortening said actuating member, andmeans for controlling said jib, said control means comprising aconnection pivotally attached between the end of the shorter arm of saidjib and an anchorage on said support intermediate of the heel pivot ofthe strut and the anchorage of the actuating member.

l. In a crane structure comprising a support, a strut pivoted at itsfoot to said suppcrt, a rocking jib eccentrically pivotec a the head ofsaid strut and means for suspending the load from the longer arm of saidjib, the combination of an actuating member piveta attached between theend of the shorter arm of said jib and an anchorage on said support,said actuating member comprising a sheath, a nut mounted on said sheath,a threaded shaft engaging said nut, means for producing relativerotation between said shaft and said nut to lengthen and shorten saidactuating ineinl er, and means for controlling said jib, said controlmeans comprising a connection pivotally attached between the end of theshorter arm of said jib and an anchorage on said support intermediate ofthe heel pivot of the strut and the anchorage c-f the actuating member.

5. In a crane structure comprising a support, a strut pivoted at itsfoot to said support, a rocking jib eccentrically pivoted at the head ofsaid strut and means for suspending the load. from the longer arm ofsaid jib, the combination of an actuating member comprising a sheath theupper end of which is pivotally attached to the end of the shorter armof said jib, a nut fixed in the lower end of said sheath, a threadedshaft engaging said nut, a bracket on said support, a carrier pivotallymounted on said. bracket and form ing an anchorage for s i l shaft,means mounted in said carrier for rotating said shaft to lengthen andshorten said actuating member, and means for controlling said jib, saidcontrol means comprising a connection pivotally attached between the endof the shorter arm of said jib and an anchorage on said supportintermediate of the heel pivot of the strut and the anchorage of theactuating member.

6. In acrane structure for use as a ships davit comprising a support, astrut pivoted at its foot to said support, a rocking jib eccentricallypivoted at the head of said strut and means for suspending the boat fromthe longer arm of said jib, the combination of a heel fitting on saidstrut, a support for the boats keel on said heel fitting, a chock'forsaid boat on the outboard face of said strut, detachable gripes forsecuring said boat against said strut, an actuating member comprising asheath the upper end of which is pivotally attached to the end of theshorter arm of said jib, a nut fixed in the lower end of said sheath, athreaded shaft engaging said nut, a bracket on said support, a carrier'pivotally mounted on said bracket and forming an anchorage for saidshaft, means mounted in said carrier for rotating said shaft to lengthenand shorten said actuating member, and means for controlling said jib,said control means comprising a connection pivotally attach ed betweenthe end of the shorter arm or" said jib and an anchorage on said supportintermediate of the heel pivot of'the strut and the anchorage of theactuating member.

7. In a crane structure for use as a ships 'davit comprising a support,a strut pivoted at its foot to said support, a rocking jib eccentricailypivoted at the head of said strut and means for suspending the boat fromthe long er arm of said jib, the combination of a heel fitting on said.strut, a support for the boats keel on said heel fitting, a chock forsaid boat on the outboard face of said strut, detachable gripes forsecuring said boat against said strut, an actuating member comprising asheath the upper end of which is pivotally attached to the end of theshorter arm of said jib, a nut fixed in the lower end of said sheath,

a threaded shaft engaging said nut, a bracket on said support, a carrierp'ivotally mounted on said bracket and forming an anchorage for saidshaft, means mounted in said carrier for rotating said shaft to lengthenand shorten said actuating member, and means for controllin said jib,said control means comprising tension rods pivotally attached to the endof the shorter arm of said jib, elongated eyes at the lower ends of saidrods, said eyes en- 'aging anchorages on said support between the heelpivot of the strut and the anchorage of the actuating member.

In testimony whereof, we affix our signatures.

LENNARD CONSTANTINE BURRILL. HARRY BOCLER. NORMAN MACLEOD HUNTER.

